1. Field of the Invention
This invention relates to a table positioning device for positioning a moving table which can be moved two-dimensionally or rotated on a reference plane, at a desired position or rotational angular position with high accuracy.
More specifically, this invention pertains to a table positioning device having a high rigidity table moving mechanism which is constituted to contribute to reduction in size and cost thereof.
2. Related Art Description
Generally, X-Y table mechanism has a fixed table, an X-axis table mounted on the fixed table in a matter that it is allowed to move linearly and reciprocally in the X-axis direction, a Y-axis table mounted on the X-axis table in a manner that it is allowed to move linearly and reciprocally in the Y-axis direction, and a linear drive mechanism for moving these tables so as to position them two-dimensionally at a desired position.
Further, X-Y table mechanism has a clamping mechanism for clamping the tables at a desired position after they are moved to the desired position. When the table are moved to another position, clamping by the clamp mechanism is released to allow the tables to move freely, and the linear drive mechanism is driven to move the tables.
A main object of this invention is to provide a table positioning device which has a table moving mechanism for moving tables on a reference plane, wherein the table moving mechanism is constituted to have a high rigidity, and to reduce in size and cost thereof.
In order to achieve the above and other objects, according to this invention, there is provided a table positioning device which has a fixed table formed on its surface with a reference plane, a moving table supported on the fixed table in a manner that it is allowed to move two-dimensionally on the reference plane, and a plurality of table moving mechanisms for moving the moving table on the reference plane, characterized in that each of the table moving mechanism comprises a servo motor, an eccentric cam which is rotated by the servo motor, and first and second parallel plates fixed on the moving table in a manner that the eccentric cam is sandwiched between them, whereby eccentric rotational motion of the eccentric cam is converted into linear motion of the moving table.
The table moving mechanisms may include first, second and third table moving mechanisms of the same structure. In this case, it is preferable for the table positioning device to have first, second and third sensors for detecting respective amounts of movement of the moving table caused by the respective first to third table moving mechanisms.
Further, it is also preferable that the first and second table moving mechanisms are designed to move the moving table in a first direction at different positions, and the third table moving mechanism is to move the moving table in a second direction perpendicular to the first direction. With this configuration, the amount of eccentric rotation of the eccentric cam in each of the table moving mechanisms is controlled, so that linear movement and rotation of the moving table can be realized.
On the other hand, according to this invention, there is provided a table positioning device which has a fixed table formed on its surface with a reference plane, a moving table supported on the fixed table in a manner that it is allowed to move two-dimensionally on the reference plane, and a plurality of table moving mechanisms for moving the moving table on the reference plane, characterized in that:
the table positioning device has a table position detecting means for detecting a position of the moving table, a clamp mechanism for clamping the moving table, and a control means for controlling the table moving mechanisms and the clamp mechanism to position the moving table at a desired position based on a detected position of the moving table by the table position detecting means, wherein
the table moving mechanisms include at least first, second and third table moving mechanisms, each of which has a linear moving mechanism for moving the moving table linearly, and wherein
the linear moving mechanism has a servo motor which is controlled and driven by the control means, an eccentric cam which is rotated by the servo motor, and first and second parallel plates fixed on the moving table in a manner that the eccentric cam is sandwiched between them, whereby eccentric rotational motion of the eccentric cam is converted into linear motion of the moving table.
The table position detecting means preferably includes first, second and third position sensors for detecting movement amounts of the moving table caused by the respective eccentric cams.
Further, it is also preferable that the first and second table moving mechanisms are designed to move the moving table in a first direction at different positions, and the third table moving mechanism is to move the moving table in a second direction perpendicular to the first direction. With this configuration, the amount of eccentric rotation of the eccentric cam in each of the table moving mechanisms is controlled, so that linear movement and rotation of the moving table can be realized.